Apparatus for dry-spinning artificial textile fibers with recovery of the volatile solvents



March 28, 1933. E. VIVIAN! 15,02,922

V APPARATUS FOR DRY SPINNING ARTIFICIAL TEXTILE FIBERS WITH RECOVERY 0F THE VOLATILE SOLVENTS Filed Sept. 19, 1928 Patented Mar. 28, 1933 UNITEDSTATES ETTOREYVIVIANI, OF ITALY nrrAnnrus non 'DRY-SPILNNIQENG ARTIFICIAL TEXTILE Frame WITH v a THE voLATILE SOLVENTS 7 Application filed Sieptember 19, 1928, Serial 170,306,940, italy April], 1928. v

In operating the so-called dry-spinning process (particularly when "acetylcellulose and nitrocellulose solutions are employed) the recovery of the volatilesolvents passing off i in the form of vapor has hitherto been effected in a great variety of ways. Allthese Ways, however, where characterized inthat the air (or other gas) ladenwith the Vapors of the solvent and removed from the spinning '10 cell, was-Wholly or partially freed fromsaid vapors. The removal of the solvent-laden air was effected by means of pumps or fans, and in all cases the gaseous mixture, consist- 3 ing of air and solvent vapors, was withdrawn 7 from the spinning cell, so that the gaseous mixture in the interior of the cell was in a continuous state of flow; a

h This circumstance indirectly entailed the necessity for cooling the whole of the gaseous 2'0 mixture led out of the cell, and for reheat-V ing it after the recovery of the'solvent.

In other words, it was always" necessary in practice to heat and cool largevolumes of air or gas, whereas all that should really be "2'5 needed is tointroduce and remove the amount I of heat required for the vaporizationand condensation, respectively, of the solvent;

The object of the present invention is to obviate the aforesaid drawbacks, or at least to restrict the cooling and'subsequent heating of the gaseous mixture present in the cell to I a'small. quantity thereof. The invention, which enables the spinning to be conducted in closed cells, renders it unnecessary to remove and cool the gaseous mixture which fills the spinningjcell, byproviding a limited surface wvhich is cooled to an adequate degree, in the spinning cell itself. This temperature should be so calculated that it does not exceed 40 the temperature of the spinning cell (measured in the immediate vicinity of the filament) and is, in any event, below'the boiling pointrof the solvent or solvents;

. If'thevapor tension of the solvent in the spinning cell exceeds thevalue corresponding to the temperature of the coolest spot within the cell, then condensation" will take place there. Consequently, inthejcell foriningthe I subsequent of the present invention, the gaseous andliquid phases of the solvent" or solv- RECOVERY or cuts are alwayspresent, in addition to'the spinning solution issuing from the nozzle.

The solvent or solvents present in theliquid state are alone continuously withdrawn, a

Fig.1 is a diagrammatic vertical section.

tio'n. w V r According to Fig. 1' the jackets'p'ace B enables thespinning cell A to be warmed by means of hot air, hot; Water or steam. In-, side the cell are disposed one or more tubes C through which cold water orbrine is circa lated for cooling purposes. V 'As' already mentioned, the vaportension of the s'olvent'vapors formed during the spin ni'ng process tends to attain the value cor- I Fig. 3 is a similar view bf anothermodifi'caso I responding to thetemperature of the cooling 'device. fThe cooling, water or brine enters the. tube Czat C" and issuestherefrom atE.

F is the spinning nozzle, and H the winding bobbin, I If now the spi ning cell be heated in sucha manner thatrapid and com l tevaporization of the'solve'nt'containedzin the spinning solution issuing from the spinning j nozzle takes place, continuous condensation occur on the coohn'g sura face, s nce the vapor tension hcann'ot'exceed a of the solvent will certain value. The condensatecan be readilly removedby way of the' funnelDi and co lectedr' r I V .The a paratu's may, of course, vary in de-- signs T us,in Fig; 2 thecooler consist'sof a'* plain tube C through which water or brine fis circulating. In this case the condensed solvents collect in p the lowermost part "of the spinning cell, and are drawn oil through the the invention as cla ms- I V I I heating coils, electrical resistance and so forth, without departing fromthe scope of the invention;

Fig. 3 represents still another embodiment. Here the cooler is confined to the lowermost part of the cell. The upper part is heated by the liquid circulating in the heating acket B, which it enters at T and leaves at The lower part is cooled by the cooling jacket B through'which water or brineat a suitable temperature is circulated. This latter arrangementinsures a quiescent filament during the spinning process, since the gentle currents resulting from the sinking of the vapors from the hot to the coldlzone of the cell facilitate the spinning process itself.

'Byv means of the apparatus herein described, 90-95% of thesolvent contained in the spinning solution can always be recovered and, underfavorable conditions, still higher values are obtained. The amount of solvent retained in the wound filament is small, and, if proper temperatures be maintained, does not exceed 5% of the weight of the fiber. v x

The solvents recovered in this manner are in a high state of purity, and can be used again without intermediate distillation.

Obviously, the invention, is notrestricted to the embodiments specified, and it will be I I art1fic1al textile fibers with recoveryof the readily understood that variations may be made without departing from the scope of defined by the appended I claim 5 r 1. In the apparatusfor dry spinning artificial textile fibers with recovery of the solvent contained in the spinning solution, the combination of a spinning cell provided with a spinning nozzle, means'for eflecting vaporization and condensation of the solvent within the cell while in direct open communi cation with the body of thevapors therein, and means for collectingithe condensate.

. I 2. In apparatus for dry-spinning artificial textile' fibers with recovery of the solvent contained in thespinning solution, thecombination of a spinningcell provided with a spinning nozzle, means for efi'ecting vapori- 'zation and condensation of the solvent so that the cell contains solvent the gaseous and liquid condition addition to the spinning solution issuing from the nozzle, and

means for withdrawing only the solvent present in liquid form from the cell whereby the vapor tension. of the solventvapors is maintained at constant value duringthespinning process I 3. In apparatus for. dry-spinning artificial textile fibers with recovery ofwthe solvent contained-in the spinningsolution, the combination of a spinning cell and means in the cell for condensing the solvent vapors and recovering thesolvent. I

4. In apparatus for dry-spinning artificial textile fibers with recovery of thesolvent conchanging the, average temperature of the gase ousmedia filling the cell, and means for collecting the condensate. I

1 6. In apparatus for dryspinning artificial textile fibers with recovery of the solvent contained in the spinning solution, the combination of a spinningcell, means for condensing the solvent vapors inside the cell without changingthe average temperature of. the gaseous media filling the ,pell, and.

means for withdrawing the condensed solvent from the cell. 7 I p f 7. A spining cell for use in dry-spinning 'artificial textile fibers with recovery of the solvent .cont-ained in the spinning solution having, in combination, means for heating the cell, and meansin thecell for condensingsolvent vapors. I z I I v 8. A spinning cell for. use in dry-spinning solvent contained in the spinning solution having, in combination, means forheating solvent contained in the spinning solution having, in combination, means for heating the upper portion of the cell,' means for cool ing the lower portion ofthe cell to the'tem- 'tained in the spinning solution, the combina- I perature of condensation of the solvent vapor's'within the 'cell, and means for collecting'the condensate.

10, A sp'inn g cell for use in dry-spinning artificial textile fiberswith recovery of the "solvent containedin the spinning solution having, "in comblnation, a acket for'thecir culation of a heating medium. surrounding the cell, cooling means for condensing. sol vent vapors within the cell, andmeans for I "collecting thecondensate. i

11; A spinning'cell for use in .dry spinning f artificial textile fibers with recovery of the;

solvent containedfin the spinning solution having, in combinatiom'means torheating V the upper portion "of the .cell,means for cooling the lower portion of the cell to'the temperature I of condensation of the solvent artificial textile fibers with solvent contained in the spinning solution,

vapors within the cell, and means including a siphon for collecting and withdrawing the condensate from the cell.

12. A spinning cell for use in dry spinning vapor. V i I 15. A process of dry spinning artificial silk including continuous extrusion of a spinning solution into a cell, continuously passing over the filament thus formed a heated gas in which the solvent evaporates, and;

continuously condensing within the cell the solvent from said gas.

16. A process as set forth in claim 15 :in

which the heated gas passes through the upper portion of the cell and is condensed the lower portion of the cell.

ETTORE VIVIANI.

recovery of the I n a process of dry-spinning artificial the step which comprises. condensation Within the cell of the solvent 

